Our favorite type of cord we like to use is the "Softglass". It is like rubber cord but is slightly translucent, very strong, yet flexible and almost looks like frosted glass. It has a hole going through the center which is perfect for stringing wire through. I like to use "softflex" wire in this case and even though it isn't necessary, I prefer the 49 strand due to it's strength and flexibility so the softglass cord can still drape nicely.
Another type of cord we recently discovered is a stainless steel cable that is nylon coated. They come in a variety of colors with a screw barrel type clasp. I prefer to cover this clasp with clay so it is more comfortable on the neck and easier to handle. These cables work great for shorter (16-18") choker type necklaces. They are also great when you really want to show off the pendant or beads and not have the cord as a distraction.
I sell these with the finished clasps in our Art Fire and Etsy shops as they are great if you want a simple cord to use for interchanging pendants. These cables work great for beaded style chokers as well making them more versatile. We have them in silver and gold and will have more colors available soon.
My latest discovery, however, is combining these cables with the softglass cord. I found there is a slight "walking" problem when using these cables on a pendant so I was experimenting with ways to "lock" them in. When I cut small pieces of the softglass and thread them on the cable they look like little beads but are also nonslip and gently keep the beads or pendant in place. I can use the softglass pieces in contrasting colors like beads or in the same color as the cable to blend in.
This new style will work well with some of the new clay designs I'm working on and will be available in the new year.